Introduce ViewRoot to forward input/view events to native

ui/android/view_android.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_ANDROID_VIEW_ANDROID_H_
 #define UI_ANDROID_VIEW_ANDROID_H_
 
 #include <list>
 
 #include "base/android/jni_weak_ref.h"
 #include "base/memory/ref_counted.h"
 #include "ui/android/ui_android_export.h"
 #include "ui/gfx/geometry/rect_f.h"
 
 namespace cc {
 class Layer;
 }
 
 namespace ui {
 
+class ViewClient;
 class WindowAndroid;
 
 // A simple container for a UI layer.
 // At the root of the hierarchy is a WindowAndroid, when attached.
 class UI_ANDROID_EXPORT ViewAndroid {
  public:
   // Stores an anchored view to delete itself at the end of its lifetime
   // automatically. This helps manage the lifecyle without the dependency
   // on |ViewAndroid|.
   class ScopedAnchorView {
@@ skipping 16 matching lines @@
    private:
     // TODO(jinsukkim): Following weak refs can be cast to strong refs which
     //     cannot be garbage-collected and leak memory. Rewrite not to use them.
     //     see comments in crrev.com/2103243002.
     JavaObjectWeakGlobalRef view_;
     JavaObjectWeakGlobalRef delegate_;
 
     // Default copy/assign disabled by move constructor.
   };
 
-  // A ViewAndroid may have its own delegate or otherwise will
-  // use the next available parent's delegate.
-  ViewAndroid(const base::android::JavaRef<jobject>& delegate);
+  explicit ViewAndroid(ViewClient* client);
+  ViewAndroid();
 
-  ViewAndroid();
   virtual ~ViewAndroid();
 
   // Returns the window at the root of this hierarchy, or |null|
   // if disconnected.
   virtual WindowAndroid* GetWindowAndroid() const;
 
   // Used to return and set the layer for this view. May be |null|.
   cc::Layer* GetLayer() const;
   void SetLayer(scoped_refptr<cc::Layer> layer);
 
   void SetDelegate(const base::android::JavaRef<jobject>& delegate);
 
   // Adds this view as a child of another view.
   void AddChild(ViewAndroid* child);
 
   // Detaches this view from its parent.
   void RemoveFromParent();
 
+  bool has_event_handler() { return has_event_handler_; }

[boliu, 2016/12/06 23:15:46]

private

[Jinsuk Kim, 2016/12/07 12:36:28]

Removed.

+
+  // Called when an |EventHandler| gets associated with the current ViewAndroid.
+  // The |EventHandler| must be unique in the tree to which this ViewAndroid

[boliu, 2016/12/06 23:15:46]

"unique in the tree" is not the phrase here, I don't have a good phrase either,
so just skip that part and describe what the condition actually is

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+  // belongs - i.e. there must be no parent or child ViewAndroid instance that
+  // already has an |EventHandler|.
+  void OnSetEventHandler();
+
   bool StartDragAndDrop(const base::android::JavaRef<jstring>& jtext,
                         const base::android::JavaRef<jobject>& jimage);
 
+  gfx::Size GetPhysicalBackingSize();
+
   ScopedAnchorView AcquireAnchorView();
   void SetAnchorRect(const base::android::JavaRef<jobject>& anchor,
                      const gfx::RectF& bounds);
 
+  // Internal implementation of ViewClient forwarding calls to the interface.
+  void OnPhysicalBackingSizeChanged(int width, int height);
+
+  void UpdateLayerBounds();
+
  protected:
   ViewAndroid* parent_;
 
  private:
   void RemoveChild(ViewAndroid* child);
 
+  // Checks if any ViewAndroid instance in the tree hierarchy (including
+  // all the parents and the children) has |EventHandler| already.
+  bool HasEventHandlerInTreeHierarchy();
+
+  // Checks if any children (plus this ViewAndroid itself) has |EventHandler|.
+  bool HasEventHandlerInSubtree();
+
   // Returns the Java delegate for this view. This is used to delegate work
   // up to the embedding view (or the embedder that can deal with the
   // implementation details).
   const base::android::ScopedJavaLocalRef<jobject>
       GetViewAndroidDelegate() const;
 
+  int GetPhysicalBackingSizeWidthPix();

[boliu, 2016/12/06 23:15:46]

remove these two

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+  int GetPhysicalBackingSizeHeightPix();
+  void SetPhysicalBackingSize(int width, int height);
+
   std::list<ViewAndroid*> children_;
   scoped_refptr<cc::Layer> layer_;
   JavaObjectWeakGlobalRef delegate_;
+  ViewClient* const client_;
+
+  int physical_width_pix_;
+  int physical_height_pix_;
+  bool has_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_VIEW_ANDROID_H_